Method of engine surge discrimination

Abstract

A method of discriminating between spurious and genuine surges in a gas turbine engine is disclosed which includes the steps of receiving an engine speed signal over a global engine surge investigation region having a plurality of temporal regions in which engine surge events can occur, identifying a specific temporal region in which an engine surge event occurs, incrementing a surge counter corresponding to the temporal region in which the engine surge event occurred by a magnitude of two, identifying the temporal regions in which no engine surge event occurred, decrementing a surge counter corresponding to each temporal region in which no engine surge event occurred by a magnitude of one; and enabling a surge avoidance flag when the magnitude of the surge counter has reached a predetermined value.

What is claimed is:  
     
         1 . A method of discriminating between spurious and genuine surges in a gas turbine engine comprising the steps of: 
 a) receiving an engine speed, signal over a global engine surge investigation region having a plurality of temporal regions in which engine surge events can occur;    b) identifying a specific temporal region of the global engine surge investigation region in which an engine surge event occurs;    c) incrementing a surge counter corresponding to the specific temporal region of the global engine surge investigation region in which the engine surge event occurred;    d) identifying the specific temporal regions of the global engine surge investigation region in which no engine surge event occurred;    e) decrementing a surge counter corresponding to each specific temporal region of the global engine surge investigation region in which no engine surge event occurred; and    f) enabling a surge avoidance flag when a surge counter corresponding to one of the temporal regions reaches a predetermined value.    
     
     
         2 . A method according to  claim 1 , wherein the step of incrementing a surge counter corresponding to a temporal region of the global engine surge investigation region in which the engine surge event occurred comprises incrementing said surge counter by a magnitude of two.  
     
     
         3 . A method according to  claim 1 , wherein the step of decrementing a surge counter corresponding to each temporal region of the global engine surge investigation region in which no engine surge event occurred comprises decrementing said surge counter by a magnitude of one.  
     
     
         4 . A method according to  claim 1 , wherein the step of enabling a surge avoidance flag includes enabling a surge avoidance flag when the magnitude of a surge counter is at least equal to five.  
     
     
         5 . A method according to  claim 1 , further comprising the step of resetting each of the surge counters when power to an engine control unit goes to zero.  
     
     
         6 . A method according to  claim 1 , further comprising the step of providing a global surge investigation region with five temporal regions in which engine surge events can occur.  
     
     
         7 . A method according to  claim 1 , further comprising the step of modifying baseline engine control schedules in response to an engine surge avoidance flag.  
     
     
         8 . A method according to  claim 7 , further comprising the step of storing a modification to baseline engine control schedules in non-volatile memory for subsequent application.  
     
     
         9 . A method of discriminating between spurious and genuine surges in a gas turbine engine comprising the steps of: 
 a) receiving an engine speed signal over a global engine surge investigation region having a plurality of temporal regions in which engine surge events can occur;    b) identifying a specific temporal region of the global engine surge investigation region in which an engine surge event occurs;    c) incrementing a surge counter corresponding to the specific temporal region of the global engine surge investigation region in which the engine surge event occurred by a first magnitude;    d) identifying the specific temporal regions of the global engine surge investigation region in which no engine surge event occurred;    e) decrementing a surge counter corresponding to each temporal region of the global engine surge investigation region in which no engine surge event occurred by a second magnitude that is less than the first magnitude; and    f) enabling a surge avoidance flag when the magnitude of a surge counter corresponding to one of the temporal regions reaches a predetermined value.    
     
     
         10 . A method according to  claim 9 , wherein the step of incrementing a surge counter corresponding to a temporal region of the global engine surge investigation region in which the engine surge event occurred comprises incrementing said surge counter by a magnitude of two.  
     
     
         11 . A method according to  claim 9 , wherein the step of decrementing a surge counter corresponding to each temporal region of the global engine surge investigation region in which no engine surge event occurred comprises decrementing said surge counter by a magnitude of one.  
     
     
         12 . A method according to  claim 9 , wherein the step of enabling a surge avoidance flag includes enabling a surge avoidance flag when the magnitude of a surge counter has reached a value that is at least equal to five.  
     
     
         13 . A method according to  claim 9 , further comprising the step of resetting each of the surge counters when power to an engine control unit goes to zero.  
     
     
         14 . A method according to  claim 9 , further comprising the step of providing a global surge investigation region with five temporal regions in which engine surge events can occur.  
     
     
         15 . A method according to  claim 9 , further comprising the step of modifying baseline engine control schedules in response to an engine surge avoidance flag.  
     
     
         16 . A method according to  claim 15 , further comprising the step of storing a modification to baseline engine control schedules in non-volatile memory for subsequent application.  
     
     
         17 . A method of discriminating between spurious and genuine surges in a gas turbine engine comprising the steps of: 
 a) receiving an engine speed signal over a global engine surge investigation region having a plurality of temporal regions in which engine surge events can occur;    b) identifying a specific temporal region of the global engine surge investigation region in which an engine surge event occurs;    c) incrementing a surge counter corresponding to the temporal region of the global engine surge investigation region in which the engine surge event occurred by a magnitude of two;    d) identifying the temporal regions of the global engine surge investigation region in which no engine surge event occurred;    e) decrementing a surge counter corresponding to each temporal region of the global engine surge investigation region in which no engine surge event occurred by a magnitude of one; and    f) enabling a surge avoidance flag when the magnitude of the surge counter corresponding to one of the temporal regions has reached a predetermined value.    
     
     
         18 . A method according to  claim 17 , wherein the step of enabling a surge avoidance flag includes enabling a surge avoidance flag when the magnitude of a surge counter has reached a value that is at least equal to five.  
     
     
         19 . A method according to  claim 17 , further comprising the step of resetting each of the surge counters when power to an engine control unit goes to zero.  
     
     
         20 . A method according to  claim 17 , further comprising the step of providing a global surge investigation region with five temporal regions in which engine surge events can occur.  
     
     
         21 . A method according to  claim 17 , further comprising the step of modifying baseline engine control schedules in response to an engine surge avoidance flag.  
     
     
         22 . A method according to  claim 21 , further comprising the step of storing a modification to baseline engine control schedules in non-volatile memory for subsequent application.